Allogeneic Red Cell Transfusion and Its Influence on Relevant Humoral and Cellular Immunological Parameters

All patients undergo the identical anesthesiological procedure, including premedication, general anesthesia with endotracheal intubation, monitoring and postoperative pain therapy and mobilization.Surgery is performed by the identical team performing a standardized technique.

Transfusion regimen The 'trigger' for homologous red cell transfusion intra- and postoperatively is the actual hematocrit concentration. Transfusion depends on discretion of the treating physicians. Number of units transfused, amount of blood loss, time, reasoning and decision maker are recorded.

Blood samples Within the kind of surgical procedures chosen for this study the chance of red cell transfusion is about 60 - 70%. In terms of figures 10 non-transfused cases could be gained within 40 cases in total. However, transfusion or non-transfusion does not happen in a row. We expect the total number of patients with blood withdrawal to be between 50 and 60. Additionally withdrawn samples currently not used for analysis will stored for further studies.

The purpose to include non-transfused otherwise fully comparable patients is to distinguish between trauma (operation) and transfusion and their influence on immune modulation. Within the studies about blood transfusion and immune modulation only some few made this differentiation. In patients with colorectal cancer surgery randomized groups with autologous predonation and patients with allogeneic transfusion only have been compared. However, within the latter (allogeneic) group of 27 patients only 13 had to be transfused, thus creating a non-transfusion group of 14 patients. These 14 non-transfused patients remained within the study being compared with autologous and allogeneic transfused patients. Operative trauma and allogeneic transfusion both increased the secretion of several cytokines including tumor necrosis factor (TNF) alpha and Interleukin-10; this effect was less pronounced in patients with autologous- and without any transfusion. Another group studied forty three orthopedic patients with total knee- or hip-arthroplasty, initially to compare autologous to allogeneic red cell transfusion. They had to change their protocol due to the small number of allogeneic transfusions (8 of 43). Including perioperatively transfused patients only (n = 37) they found an increase in immune regulatory cytokine Interleukin (IL)-10 after red cell transfusion, which was most pronounced 7 days after surgery, whereas there was only a mild increase in non- or autologous transfused patients. Unfortunately they did not differentiate between autologous-and non-transfused patients. Thus their data could not reveal the effect of surgery itself on the analyzed parameters.